Lamp-rheostat.



PATENTED MAR. 20, 1906.

T. J. BULL.

LAMP RHEOSTAT.

APPLICATION FILED JUNE 15. 1903.

UNITED sTATEs PATENT OEEIOE. i

Specicaton of Letters Patent.

Patentedlarch 20, 1906.r

Application ned June 15, 1903. serial Nd. 161,439..

To a/LL whom it may concern:

Be it known that I, THOMAS J. BULL, aV citizen of the United States, and a resident of the city, county, and State of New York, have invented certain new and useful Imrovements in Lam Rheostats, of which the ollowing is a spec' cation.

My invention relates to lam -rheostats; and it has for an object to provid a rheostat adapted for use in connection with ordinary electric-lighting currents.

A special obJect of myinvention is to provide a rheostat for reducing the potential of an' electric-lighting circuit to that adapted for use in a miniature incandescent lamp and at the-same time to provide means for adjusting the potential as required to compensate for variations of potential at different points along the lighting-circuit. A y

My invention also has for an object to rovide a rheostat whereby the potential o an electric circuit may be reduced to different steps andthe potential of each step accurately adjusted.

My invention also has for an obj ect to -provide a rheostat including an incandescent lam as` one element of the high-resistance me ium, the construction being such that the lamp is inclosed within a substantially light-proof casing without unduly enlarging the apparatus and at the same time without producing a structure which will become undul heated when in use.

hese and other objects of my invention will more fully appear from the following description.

My invention consists in the novel parts, improvements, and combinations herein shown and described.

The accompanyin drawings, which are referred to herein and orm a part hereof, illustrate one embodiment of my-invention and serve in connectionwith the description herein to explain the princi les thereof and the best mode contemplate by mev of carrying the invention into effect.

Of the drawings, lFi ure 1 is a longitudinal central section of a reostat constructed in accordance with m invention, taken on the line 1 1 of 3. `i 2 is a side elevation of the device, part of tie casing being broken away and certain parts shown in section to more clearly illustrate the construction. Fig. 3 is an end view of the device as seen from the to in Figs. 1 and 2, the casing being remay include the resistance-coil alone..

as seen from the bottom of F v1 and 2, and Fig. 5 is a diagrammatic view illustrating the electric connections involved in the construction of the device. Y

A rheostat constructed in accordance with one feature of myin'vention comprises a highresistance coil and an'incandescent lamp-inclosed within lsaid coil and arranged to be connected in series therewith. In' the best embodiment of the invention means are also provided for shunting the current around more or less of the resistancecoil, whereby the potential of the circuit may be varied. Where` the device is to beused to reduce the potential of an electric circuit to different' steps, means are also provided whereby the working circuit may include the incandescent lamp and the resistance-coil in series or accordance with the best embodiment of thiseature of the invention three terminals or bindingosts are provided for establishing the auxi iary or working circuit, one of these posts being connected with one pole of the supply-circuit through the resistancecoil alone, another being connected with the other i ole of the supply-circuit through the incan escent lamp, and the other bein connected directly with the last-mentione pole of thesup ly-circuit. When an incandescent lainv is used as one element-of the resistance me ium and is inclosed within the re.-

sistance-coil,vv the frame and casing of thedevice are preferably so constructed asto permit a free circulation of the air around the lamdpi).

Referring now to -the particular.' embo ment of my invention illustrated in the drawings, the numerals 1 and 2 represent oppo- 'f ypieces between which a cylin er3is clam ed, y

sitely-arranged disk-like sup Orts or framesaid frameieces 1 and 2 being connecte yby lmeans of t e bindingscrews 4 and 5. The

metal piece or sleeve 8, which, as shown, isv

threaded to it the ordinary incandescentlamp socket'.l This iece 8 ma of course be iven the required s ape to a apt it to any orm of socket. The projection 7 1s preferably and, as shown, provided with an inner l is arranged to engage the thread in the shaft recess adapted to receive a socket 9, which is constructed to receive the pole-piece of a suitable incandescent lamp 11. The socket 9 is retained in the recess of the projection 7 by means of a binding-screw 12, which is insulated from the socket-piece 9`by the insulator v13 and is adapted to make contactwith the end pole of the lamp 1 1, the nut 14 for the screw 12 serving at the same time to form one of the poles ofthe rheostat, the other ole of which is formed by the sleeve 8,. The arnepiece 2 of the device is provided with a central opening 15 and withl three lugs 16, 17, and 18 and adapted to support the three bindingosts 19, 20, and 21. The frame-piece 2 is a so provided with an integral lug 22, through which a shaft 23 passes and finds its bearing. The shaft 23 is arranged parallel with the resistance-coil' and, as shown, is

given a bearing at its opposite end in a suitable opening in the frame-piece 1. The shaft is provided at the end which projects through the lug 22With a thumb-wheel 24, and it is constructed along the part between the framepieces 1 and 2 with a thread, preferably of high pitch, substantiallyl as shown. Fitted on the threaded portion of the shaft 23 is a slide 25, which is provided with a spring contact-plate 26, adapted-to make contact with a suitable bared .portion of the coil'6. The plate 26 preferably, also, is turned out slightly at one oi its ends, as shown in dotted lines in Fig. 4, so as to make sliding contact with the binding-screw 5. For the purpose of making the device compact the coil-supporting cylinder 3 is preferably eccentrically arranged with relation to the frame-pieces 1 and 2, said pieces being to this end provided with eccentric recesses adapted to receive the ends of the cylinder 3.

The device is inclosed in a casing which preferably and as shown comprises a cylindrical portion 28, which has a flanged end 29 adapted to embrace the periphery of the frame-piece 1, and a circular end portion 30, which is provided with a flange-piece 31, adapted to overlie the frame-piece 2 and embrace the end of the cylinder 28. The sections 28 and 30 of the casing are preferably removably secured together by means of suitable screws-32. Forthe purpxose of providing a free circulation of au'l t rough the device to prevent the same from becoming hot While in operation the sections 28 and 30 of the casing are preferabl perforated, 'and the frame-piece 1 is also pre erably provided with suitable openings 33. The part 28 is preferably provided with a longitudinal slit 34, arranged in parallel relationwith the shaft 23, so that a screw 35, projecting from the lslide 25, may project through the casing, whereb it may be provided with a pointer 36 to indicate the position ofthe slide. In accordance with the preferred construction the screw 35 23, vso as to cause the slide to be 'moved bythe revolution of that shaft.

The electrical connections of the device are diagrammatically represented in Fig. 5. Referring to this figure, it will be seen that the coil 6 is connected with the sleeve 8 by means of a connection 37 and with the binding-post 19 by means of a connection 38. The contact-plate 25 is also connected with the binding-post 19 by means of a connection which:

for convenience is made to consti-tute the binding-screw 5. The socket 9 of the lamp 11 is connected with the bindin -post 2() by means of the connection 39, an the pole 14 of the device is connected with the bindingpost 21 by means of the connection 40. Referring now to the particular construction illustrated, the connection 37 will be seen to consist of a plate which is suitably secured to the sleeve 8 and forms a nut for the end'of the binding-screw 4, one end of the coil 6 bein'g electrically connected with said bindingscrew. The connection 38 consists of a wire which pradtically forms a continuation of the coil 6. The connection 39 consists of a Wire which is secured at one end to the clampscrew of the binding-post 20 and at the other end to a clamp-screw 41, which also clam s an arm extending from the socket 9. T e connection 4() consists of an insulated wire which is connected to the clamp-screw of the binding-post 2l at one end and is electrically connected With the binding-screw 12, being clamped between the end of the extension 7 and an insulating-piece 42, upon which the socket 9 rests.

It will be seen that by connecting the auxiliary circuit or Working circuit with the binding-posts 19 and 2O both the resistance-coil -and the lamp 11 will be included in series in the working circuit. If, on the other hand,

IOC

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the 'auxiliary circuit is connected with the burning miniature electric lamps, such as are used, for instance, by physicians in making examinations, performing operations, &c. The second circuit is particularly adapted -for heating the cautery u'sed by physlcians in making certain operations. he device as a whole 1s particularl ada ted for use by physicians by reason o -the act that the incandescent lam forming a part thereof is entirely house so that there is no objectionable light resulting from the"use of the apparatus in a dark room.

My invention in its broader aspects is not limited to the precise construction shown nor to the particular construction by which it has been or may be carried into efl'cct, as many changes may be made in the construction IIO without departing from the main principles of the invention and without sacrificing its chief advantages.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination in a rheostat of a resistance-coil and an incandescent lamp located within said coil and adapted to be connected in series therewith. i.

2. The combination in a rheostat of a resistance-coil, an incandescent lamp located within said coil and adapted to be connected in series therewith, and means for varying the effective length of the resistance-coil.

3. The combination in a rheostat of a highresistance coil, an incandescent lamp, means whereby the circuit through the device may be caused to include both the coil and the lamp in series or to include thecoil only, slibstantially as described.

4. The combination in a rheostat of a resistance-coil, an incandescent lamp located within said coil and ada ted to be connected in series therewith, an a support for said lamp and coil including a part adapted tobe secured in an incandescent-lamp socket and having poleieces adapted to connect 'the device with t 1e lamp-circuit. l 5.. The combination in a rheostat of a resistance-coil, a hollow cylindrical support -for said coil, and a lamp located within said cylinder and adapted to be connected in series with said coil.

6. The combination in a rheostat of a resistance-coil, a hollow cylindrical support for said coil, and an incandescent lamp located within said cylinder and adapted to be connected in series with said coil, and framepicces between which said cylinder is secured,

said frame-pieces having openings communieating with the interior of said cylinder.

7. The combination in a rheostat of a resistance-coil, a hollow cylindrical support for said coil, frame-pieces between which said cylindrical support is secured, means on one side of said cylinder for adjusting the effective length of said coil, said cylinder being eccentrically arranged with relation to the frame-pieces whereby space is provided for the said adjusting means. A

8.' The combination in a rheostat of a resistance-coil, a hollow cylindrical support for said coil, and an incandescent lamp located within said cylinder and adapted to be connected in series with said coil, and framepieces between which said cylinder is secured, said frame-pieces having openings communieating with the interior of said cylinder and a perforated casing inclosing said parts.

9. The combination in a rheostat of a resistance-coil, a hollow cylindrical support for said coil, an incandescent lamp located within said cylinder and adapted to be connected in series with said coil, and frame-pieces between which said cylinder is secured, said frame-pieces having openings communicating with the interior cip said cylinder, and one of said frame-pieces having a part adapted to be secured in an incandescent-lamp socket and having contact-pieces adapted to connect the rdevice with the lamp-circuit.

In'testimony whereof I have signed myy name to this specification in the presence of two subscribing witnesses.

THOMAS J. BULL.

Witnesses JOHN O. GEMPLER, EDWIN SEGER. 

